You can be proud of your son, thinking of taking his family around in Paris and elsewhere.
Of course, you all are very welcome on this side of the pond. Keep me in the loop, and I'll be happy to give you some advice about where to go and what to do. As a local, I will certainly have advice and pinion of things here a bit different from your son, who,even if he's been living here, has a visitor point of view. Of course, tell me if I can help. And if you wanna come to Marseille, it's just 3 hours by train (500 miles), I'll be happy to meet you all.